CN117727838A

CN117727838A - Solar cell, preparation method thereof and photovoltaic module

Info

Publication number: CN117727838A
Application number: CN202410175593.9A
Authority: CN
Inventors: 丘才杰; 赵世杰; 李文琪; 邢成鹏; 张婷婷; 杨洁; 郑霈霆
Original assignee: Jinko Solar Haining Co Ltd
Current assignee: Jinko Solar Haining Co Ltd
Priority date: 2024-02-07
Filing date: 2024-02-07
Publication date: 2024-03-19

Abstract

The embodiment of the application relates to the field of solar cells, and provides a solar cell, a preparation method thereof and a photovoltaic module, wherein the method comprises the following steps: providing a battery piece, wherein the battery piece comprises a first surface and a second surface which are opposite, the first surface is provided with a plurality of first grid lines, the second surface is provided with a plurality of second grid lines, and the orthographic projection of the first grid lines on the first surface is not overlapped with the orthographic projection of the second grid lines on the first surface; and carrying out first laser treatment on the first surfaces on two sides of the first grid line, and introducing first reverse current between the first grid line and the second grid line, wherein the ratio of the laser power of the first laser treatment to the preset power is 1-1.1, and the ratio of the first reverse current to the preset current is 1-1.25. The solar cell, the preparation method thereof and the photovoltaic module are at least beneficial to improving the efficiency of the solar cell.

Description

Solar cell, preparation method thereof and photovoltaic module

Technical Field

The embodiment of the application relates to the field of solar cells, in particular to a solar cell, a preparation method thereof and a photovoltaic module.

Background

In the solar cell, a plurality of grid lines are required to be formed on the surface of the cell sheet, so that the current generated by the cell sheet is collected.

The Laser assisted sintering technology is also called Laser enhanced contact optimization (Laser-enhanced contact optimization, LECO), and the main working principle of the LECO technology is as follows: the high-intensity laser irradiates the battery piece to excite charge carriers, and meanwhile, reverse voltage is applied to the grid line, so that a local current of a plurality of amperes is generated, and the corresponding grid line is sintered to cause interdiffusion between metal paste and a substrate of the battery piece, so that contact resistance between the grid line and a semiconductor substrate is reduced.

Disclosure of Invention

The embodiment of the application provides a solar cell, a preparation method thereof and a photovoltaic module, which are at least beneficial to improving the efficiency of the solar cell.

According to some embodiments of the present application, an aspect of embodiments of the present application provides a method for manufacturing a solar cell, including: providing a battery piece, wherein the battery piece comprises a first surface and a second surface which are opposite, the first surface is provided with a plurality of first grid lines, the second surface is provided with a plurality of second grid lines, and the orthographic projection of the first grid lines on the first surface is not overlapped with the orthographic projection of the second grid lines on the first surface; and carrying out first laser treatment on the first surfaces on two sides of the first grid line, and introducing first reverse current between the first grid line and the second grid line, wherein the ratio of the laser power of the first laser treatment to the preset power is 1-1.1, and the ratio of the first reverse current to the preset current is 1-1.25, wherein the preset power and the preset current are laser treatment on the first surfaces on two sides of the first grid line and reverse current introduced between the first grid line and the second grid line when the front projection of the first grid line on the first surface overlaps with the front projection of the second grid line on the first surface, so that the PN junction of the first grid line and the PN junction of the second grid line are broken down.

In some embodiments, the first surface on both sides of the first gate line includes alternately arranged laser-treated regions and non-laser-treated regions in an extending direction along the first gate line; performing first laser processing on the first surfaces on two sides of the first grid line comprises: and performing first laser processing on the laser processing areas on two sides of the first grid line.

In some embodiments, a ratio of a total length of the non-laser processing region to a total length of the laser processing region in an extending direction along the first gate line is 2:1 to 4:1.

In some embodiments, the length of the laser processing region ranges from 1 μm to 5 μm in the extending direction along the first gate line; the length of the non-laser treatment region is 3-7 μm.

In some embodiments, the first laser processing is performed on the first surfaces on two sides of the first grid line, and the method further includes: and performing first laser processing on the first grid line.

In some embodiments, the first surface includes a first laser region and a second laser region, the first laser region is located at two sides of the first grid line in a direction perpendicular to the extension direction of the first grid line, the second laser region is located at two sides of the first laser region away from the first grid line, and the orthographic projection of the second grid line on the first surface is located in the second laser region; performing first laser processing on the first surfaces on two sides of the first grid line comprises: performing first laser treatment on the first laser region; after the first laser processing, the method further comprises: and performing second laser processing on the second laser region, and introducing second reverse current between the first grid line and the second grid line, wherein the laser power of the second laser processing is larger than that of the first laser processing, and the second reverse current is larger than that of the first reverse current.

In some embodiments, the first laser region includes alternately arranged laser processing regions and non-laser processing regions in an extension direction along the first gate line; performing a first laser treatment on the first laser region includes: performing first laser processing on the laser processing area of the first laser area only; performing a second laser treatment on the second laser region includes: and performing second laser treatment on all second laser areas.

In some embodiments, the width of the second laser region is equal to the width of the second gate line in a direction extending perpendicular to the first gate line.

In some embodiments, the widths of the first laser regions on both sides of the second laser region are equal in an extending direction perpendicular to the first gate line.

According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a solar cell, which is formed by using the method for manufacturing a solar cell according to any one of the embodiments.

According to some embodiments of the present application, there is also provided a photovoltaic module according to another aspect of the embodiments of the present application, including: at least one solar cell as provided in the above embodiments; the adhesive film covers the surface of the solar cell; and the cover plate covers the surface of the adhesive film far away from the solar cell.

The technical scheme provided by the embodiment of the application has at least the following advantages:

in the method for manufacturing the solar cell, laser treatment is performed on the first surfaces on two sides of the first grid line on the cell, and meanwhile reverse current is introduced between the first grid line and the second grid line. Under the irradiation of laser, a large number of current carriers can be generated in the areas, located on the two sides of the first grid line, of the battery piece, electrons in the current carriers can be confined on the surface, in contact with the first grid line, of the battery piece due to the effect of reverse current, the electrons react with the first grid line, metal ions in the first grid line are promoted to precipitate out metal micelles, conductive contact points are formed between the first grid line and semiconductor materials in the battery piece, contact resistance between the first grid line and the semiconductor materials can be reduced, and therefore improvement of filling factors of the solar battery is facilitated, and photoelectric conversion efficiency of the solar battery is improved. In addition, as the orthographic projection of the first grid line on the first surface and the orthographic projection of the second grid line on the first surface are not overlapped, the resistance between the first grid line and the second grid line is larger than the resistance when the orthographic projection of the first grid line on the first surface and the orthographic projection of the second grid line on the first surface are overlapped, so that laser power larger than preset power and reverse current larger than preset current can be adopted when first laser processing is carried out, laser sintering of the first grid line is promoted, better ohmic contact between the first grid line and semiconductor materials in the battery piece is facilitated, the filling factor of the solar battery is improved, and the efficiency of the solar battery is further improved. The laser power of the first laser treatment is set to be 1-1.1 with the preset power, and the ratio of the first reverse current to the preset current is 1-1.25, so that the problem that a PN junction between the first grid line and the second grid line is broken down can be avoided, and meanwhile, the first grid line is good in sintering degree, so that the problem of solar cell efficiency reduction caused by excessive sintering or low sintering process is avoided.

Drawings

One or more embodiments are illustrated by way of example and not limitation in the figures of the accompanying drawings, which are not to be construed as limiting the embodiments unless specifically indicated otherwise; in order to more clearly illustrate the embodiments of the present application or the technical solutions in the conventional technology, the drawings that are required to be used in the embodiments will be briefly described below, and it is apparent that the drawings in the following description are only some embodiments of the present application, and other drawings may be obtained according to these drawings without inventive effort for a person of ordinary skill in the art.

Fig. 1 is a schematic structural diagram of a battery sheet according to an embodiment of the present disclosure;

fig. 2 is a flow chart corresponding to a method for manufacturing a solar cell according to an embodiment of the present application;

fig. 3 is a schematic structural diagram corresponding to a step of providing a solar cell in the method for manufacturing a solar cell according to an embodiment of the present disclosure;

fig. 4 is a top view of a battery body according to an embodiment of the present disclosure;

FIG. 5 is a top view of another battery plate according to an embodiment of the present disclosure;

fig. 6 is a schematic cross-sectional view of fig. 5 along the direction CC 1.

Detailed Description

As known from the background art, when the laser-assisted sintering technology forms a gate line on the surface of the battery piece, the problem that a PN junction (a boundary or interface between a p-type semiconductor material and an n-type semiconductor material in a substrate) in the substrate is broken down easily occurs due to the influence of laser or reverse voltage, so that the phenomenon that the battery piece is blackened in an electroluminescent image is caused, and the efficiency of the battery piece is affected.

Fig. 1 is a schematic structural diagram of a battery sheet according to an embodiment of the present application.

Referring to fig. 1, the battery sheet 100 has opposite first and second surfaces 101 and 102, the first surface 101 of the battery sheet 100 has a first grid line 111, the second surface 102 of the battery sheet 100 has a second grid line 112, the second grid line 112 has a different polarity from the first grid line 111, for example, the first grid line 111 is one of a positive electrode or a negative electrode, and the second grid line 112 is the other of the positive electrode or the negative electrode. Since the numbers of the first and second grid lines 111 and 112 on both side surfaces of the battery sheet 100 may be unequal, there may be a state in which a partial number of the first and second grid lines 111 and 112 are aligned in a direction perpendicular to the first surface 101, a state in which a partial number of the first and second grid lines 111 and 112 are partially aligned, and a state in which a partial number of the first and second grid lines 111 and 112 are misaligned. The alignment state of the different first and second grid lines 111 and 112 results in different resistances between the different first and second grid lines 111 and 112 when reverse current is applied between the first and second grid lines 111 and 112, and if the same laser power is applied to all of the first surfaces 101 of the battery sheet 100 and the same reverse current is applied to all of the first and second grid lines 111 and 112, the resistances between the first and second grid lines 111 and 112 when the first and second grid lines 111 and 112 are aligned or partially aligned are smaller than the resistances between the first and second grid lines 111 and 112 when the first and second grid lines 111 and 112 are in a dislocated state. That is, when the front projection of the first gate line 111 on the first surface 101 and the front projection of the second gate line 112 on the first surface 101 at least partially overlap, the PN junction between the first gate line 111 and the second gate line 112 is more likely to break down. Further, blackening occurs in the electroluminescent image of the battery sheet 100, which affects the efficiency of the solar cell.

The embodiment of the application provides a preparation method of a solar cell, which is at least beneficial to improving the efficiency of the solar cell.

Embodiments of the present application will be described in detail below with reference to the accompanying drawings. However, as will be appreciated by those of ordinary skill in the art, in the various embodiments of the present application, numerous technical details have been set forth in order to provide a better understanding of the present application. However, the technical solutions claimed in the present application can be implemented without these technical details and with various changes and modifications based on the following embodiments. The method for manufacturing the solar cell according to the present embodiment will be described in detail below with reference to the accompanying drawings.

Fig. 2 is a flow chart corresponding to a method for manufacturing a solar cell according to an embodiment of the present application; fig. 3 is a schematic structural diagram corresponding to a step of providing a solar cell in the method for manufacturing a solar cell according to an embodiment of the present application.

Referring to fig. 2, a method of manufacturing a solar cell includes:

step S1: referring to fig. 3, a battery cell 200 is provided, where the battery cell 200 includes a first surface 201 and a second surface 202 opposite to each other, the first surface 201 has a plurality of first grid lines 211, the second surface 202 has a plurality of second grid lines 212, and the orthographic projection of the first grid lines 211 on the first surface and the orthographic projection of the second grid lines 212 on the first surface 201 do not overlap.

In some embodiments, the battery plate 200 may be one of a PERC cell (Passivated Emitter and Rear Cell, passivated emitter and back cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell, passivated emitter back surface full diffusion cell), a TOPCON cell (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact cell), a HIT/HJT cell (Heterojunction Technology, heterojunction cell).

In some embodiments, the battery piece 200 may be a single-sided battery, the first surface 201 may be a light receiving surface for receiving incident light, and the second surface 202 may be a backlight surface. In some embodiments, the battery piece 200 may be a double-sided battery, and the first surface 201 and the second surface 202 may both be light-receiving surfaces and may be used for receiving incident light.

In some embodiments, the battery sheet may include a first passivation layer, a substrate, and a second passivation layer stacked in this order, a surface of the first passivation layer away from the substrate being a first surface, a surface of the second passivation layer away from the substrate being a second surface, the first gate line being located on a surface of the first passivation layer away from the substrate, and the second gate line being located on a surface of the second passivation layer away from the substrate. The substrate is used for receiving incident light and generating photo-generated carriers, and the first passivation layer and the second passivation layer can prevent oxidation or corrosion of the surface of the substrate so as to improve the stability and service life of the battery piece.

In some embodiments, the material of the substrate may be at least one of monocrystalline silicon, polycrystalline silicon, amorphous silicon, or microcrystalline silicon. In some embodiments, the materials of the first passivation layer and the second passivation layer may each include one or more of silicon oxide, silicon nitride, silicon oxynitride, silicon oxycarbonitride, titanium oxide, hafnium oxide, or aluminum oxide.

In some embodiments, the substrate may be an N-type semiconductor substrate or a P-type semiconductor substrate. The N-type semiconductor substrate is doped with an N-type doping element, which may be any of v group elements such As phosphorus (P) element, bismuth (Bi) element, antimony (Sb) element, and arsenic (As) element. The P-type semiconductor substrate is doped with a P-type element, and the P-type doped element may be any one of group iii elements such as boron (B) element, aluminum (Al) element, gallium (Ga) element, and indium (In) element.

The substrate may have an emitter therein at a side of the substrate adjacent to and in contact with the first passivation layer. The doping element type of the emitter is opposite to the doping element type in the substrate, so that a PN junction is formed with the substrate. For example, the doping element in the substrate is a P-type doping element, and the doping element in the emitter is an N-type doping element; the doping element in the substrate is an N-type doping element, and the doping element in the emitter is a P-type doping element. The PN junction may receive incident light irradiated to the surface of the substrate and generate electron-hole pairs, for example, when the substrate is an N-type substrate, separated electrons move into the substrate and separated holes move into the emitter, so that current may be formed.

In some embodiments, the substrate may have a textured structure, such as a pyramid-shaped textured surface, on at least one side surface of the substrate, so that the textured structure may enhance the absorption and utilization of incident light by the substrate, thereby advantageously improving the light conversion efficiency of the battery cell. If the solar cell is a single-sided cell, a textured surface may be formed on only one side of the substrate, and the other side surface of the substrate may be a polished surface, i.e., the polished surface of the substrate is flatter than the textured surface. In the case of a single-sided battery, a textured surface may be formed on both surfaces of the substrate. If the solar cell is a double-sided cell, a suede may be formed on both side surfaces of the substrate.

In some embodiments, the material of the first passivation layer may include at least one of aluminum oxide, silicon nitride, or silicon oxynitride. The first passivation layer may have a single-layer structure or a stacked-layer structure, for example, the single-layer structure may be a single-layer aluminum oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the laminated structure can be formed by laminating at least two layers of aluminum oxide film layers, silicon nitride film layers or silicon oxynitride film layers.

In some embodiments, the material of the second passivation layer may include at least one of aluminum oxide, silicon nitride, or silicon oxynitride. The second passivation layer may have a single-layer structure or a stacked-layer structure, for example, the single-layer structure may be a single-layer aluminum oxide film layer, a single-layer silicon nitride film layer, or a single-layer silicon oxynitride film layer; the laminated structure can be formed by laminating at least two layers of aluminum oxide film layers, silicon nitride film layers or silicon oxynitride film layers.

In some embodiments, the second passivation layer may include a tunneling layer, a doped conductive layer, and an anti-reflection layer sequentially stacked along a direction away from the surface of the substrate, where the tunneling layer and the doped conductive layer are used to form a passivation contact structure, the tunneling layer may have a chemical passivation effect, and since the surface of the substrate has interface state defects, the tunneling layer may saturate dangling bonds on the surface of the substrate, reduce the defect state density on the surface of the substrate, reduce the recombination center on the surface of the substrate to reduce the carrier recombination rate, so that the interface state density on the surface of the substrate is greater, the increase of the interface state density may promote the recombination of photo-generated carriers, and increase the filling factor, the short-circuit current, and the open-circuit voltage of the solar cell, so as to improve the photoelectric conversion efficiency of the solar cell; the doped conductive layer can have a field passivation effect, and can form an electrostatic field, so that minority carriers escape from an interface, the concentration of the minority carriers is reduced, the carrier recombination rate at the interface of a substrate is lower, the open-circuit voltage, the short-circuit current and the filling factor of the solar cell are improved, and the photoelectric conversion efficiency of the solar cell is improved. The reflection reducing layer can reduce the reflectivity of sunlight on the surface of the solar cell, so that more light is absorbed and converted into electric energy, the light absorption efficiency of the solar cell is improved, the internal structure of the cell can be protected by the reflection reducing layer, the cell is prevented from being polluted by the environment, and the stability of the solar cell is improved.

The material of the tunneling layer may include at least one of silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or magnesium fluoride.

The material of the doped conductive layer may be at least one of amorphous silicon, polysilicon, or silicon carbide. The doped conductive layer is provided with the same doped element as the substrate, the doped element type of the substrate is P type, and the doped element type in the doped conductive layer is also P type; the doping element type of the substrate is N-type, and the doping element type in the doping conductive layer is also N-type.

The material of the anti-reflection layer may be one of silicon oxide, aluminum oxide, silicon nitride or silicon oxynitride.

In some embodiments, the distance from the orthographic projection of the second grid line 212 on the first surface 201 to the orthographic projection of the adjacent two first grid lines 211 on the first surface 201 is equal. That is, the second grid line 212 is located right in the middle of the adjacent first grid lines 211, so that the distances from the second grid line 212 to the adjacent two first grid lines 211 are equal, and then the resistances between the second grid line 212 and the corresponding adjacent two first grid lines 211 are equal, so that in the process of performing the first laser treatment on the first surfaces 201 on both sides of the first grid lines 211 and introducing the first reverse current between the first grid lines 211 and the second grid lines 212, the sintering degrees of the different first grid lines 211 are kept similar, and the uniformity of the solar cell performance is improved.

In some embodiments, the distance from the orthographic projection of the second grid line 212 on the first surface 201 to the orthographic projection of the adjacent two first grid lines 211 on the first surface 201 may also be unequal.

In some embodiments, the number of first gate lines may be different from the number of second gate lines. For example, the number of the second gate lines may be 2 times the number of the first gate lines. Specifically, when the number of the first gate lines on the first surface is 160, the pitch between the first gate lines may be 1.1mm to 1.5mm, for example, 1.1mm, 1.12mm, 1.33mm, 1.45mm, or 1.5mm; the number of the second grid lines on the second surface can be 320, and the spacing between the second grid lines can be 1/2-1/3 of the spacing between the first grid lines, such as 1/2, 1/2.3, 1/2.5, 1/2.8 or 1/3. When the number of the second grid lines is twice that of the first grid lines, the first grid lines can be arranged at corresponding positions in the middle of the adjacent second grid lines at intervals, so that the first grid lines and the second grid lines are completely staggered along the direction vertical to the first surface.

In some embodiments, the number of first gate lines and the number of second gate lines may be equal. For example, the number of first grid lines on the first surface may be 148, and the space between the first grid lines may be 1.1mm to 1.5mm, for example, 1.1mm, 1.12mm, 1.33mm, 1.45mm or 1.5mm; the number of second grid lines on the second surface may be 148, and the spacing between the second grid lines may be 1.1 mm-1.5 mm, for example 1.1mm, 1.12mm, 1.33mm, 1.45mm or 1.5mm. When the first grid lines and the second grid lines are printed, each first grid line can be positioned in a region between adjacent second grid lines, so that the first grid lines and the second grid lines are completely staggered.

Step S2: carrying out first laser treatment on the first surfaces 201 on two sides of the first grid line 211, and introducing first reverse current between the first grid line 211 and the second grid line 212, wherein the ratio of the laser power of the first laser treatment to the preset power is 1-1.1, such as 1, 1.01, 1.02, 1.03, 1.04, 1.05, 1.06, 1.07, 1.08, 1.09 or 1.1; the ratio of the first reverse current to the preset current is 1 to 1.25, for example, 1, 1.03, 1.05, 1.07, 1.1, 1.14, 1.18, 1.2, 1.23 or 1.25, wherein the preset power and the preset current are the laser power and the reverse current corresponding to the first surface 201 on two sides of the first grid line 211 and the reverse current introduced between the first grid line 211 and the second grid line 212 when the front projection of the first grid line 211 on the first surface 201 and the front projection of the second grid line 212 on the first surface 201 overlap, so that the PN junction of the first grid line 211 and the second grid line 212 breaks down.

In some embodiments, the preset power and preset current may be obtained by testing a test battery cell. For example, the front and back sides of the test cell may have front and back side grids, where the front projection of the front side grid on the front side of the cell completely overlaps with the front projection of the back side grid on the front side of the cell, and the manufacturing process of the test cell is the same as the manufacturing process of the cell. The laser processing is carried out on the surfaces of the two sides of the front grid line of the test battery piece, and reverse current is introduced between the front grid line and the back grid line, so that PN junctions between the front grid line and the back grid line are broken down, and laser power and reverse current when the PN junctions are broken down are obtained as preset power and preset current.

It can be appreciated that, when the ratio of the laser power of the first laser processing to the preset power is 1, in order to promote the first gate line 211 to have a better sintering degree, the ratio of the first reverse current to the preset current is greater than 1; when the ratio of the first reverse current to the preset current is 1, in order to promote the first gate line 211 to have a better sintering degree, the ratio of the laser power of the first laser processing to the preset power is greater than 1.

In the method for manufacturing a solar cell provided in this embodiment, the first surfaces 201 on both sides of the first grid line 211 on the cell 200 are subjected to laser processing, and meanwhile, a reverse current is introduced between the first grid line 211 and the second grid line 212. Under the irradiation of laser, a large number of carriers are generated in the regions of the cell 200 located at the two sides of the first grid line 211, meanwhile, electrons in the carriers can be confined on the surface of the cell 200 contacted with the first grid line 211 due to the action of reverse current, the electrons react with the first grid line 211, metal ions in the first grid line 211 are promoted to precipitate out metal micelles, the metal micelles form conductive contact points between the first grid line 211 and semiconductor materials in the cell 200, contact resistance of the first grid line 211 and the semiconductor materials can be reduced, and thus the filling factor of the solar cell can be improved, and photoelectric conversion efficiency of the solar cell is improved. In addition, since the front projection of the first grid line 211 on the first surface 201 and the front projection of the second grid line 212 on the first surface 201 are not overlapped, compared with the resistance between the first grid line 211 and the second grid line 212 when the front projection of the first grid line 211 on the first surface 201 and the front projection of the second grid line 212 on the first surface 201 are overlapped, the resistance between the first grid line 211 and the second grid line 212 is larger, so that the laser power larger than the preset power and the reverse current larger than the preset current can be adopted when the first laser treatment is performed, the laser sintering of the first grid line 211 is promoted, the better ohmic contact between the first grid line 211 and the semiconductor material in the cell 200 is facilitated, the filling factor of the solar cell is improved, and the efficiency of the solar cell is further improved. By setting the ratio of the laser power of the first laser processing to the preset power to be 1-1.1 and the ratio of the first reverse current to the preset current to be 1-1.25, the problem that the PN junction between the first grid line 211 and the second grid line 212 is broken down can be avoided, and meanwhile, the first grid line 211 is favorable to have a better sintering degree, so that the problem of the reduction of the efficiency of the solar cell caused by excessive sintering or low sintering process is avoided.

Fig. 4 is a top view of a battery plate according to an embodiment of the present disclosure.

Referring to fig. 4, in some embodiments, the first surface 201 at both sides of the first gate line 211 may include laser processing regions I and non-laser processing regions II alternately arranged in an extending direction along the first gate line 211; performing a first laser process on the first surface 201 on both sides of the first gate line 211 includes: only the laser processing regions I on both sides of the first gate line 211 are subjected to the first laser processing.

That is, in the process of performing the first laser processing, the first surfaces 201 on both sides of the first gate line 211 are subjected to the intermittent laser processing by the virtual-real combined irradiation method, the laser processing region I is subjected to the laser irradiation, and the non-laser processing region II is not subjected to the laser irradiation, so that a large number of carriers are generated in the laser processing region I, no carriers are generated in the non-laser processing region II, or fewer carriers are generated due to the irradiation of the laser processing region I. In this way, the irradiation mode of the first laser irradiation area I for patterned irradiation can accurately regulate and control the number of carriers generated, thereby being beneficial to controlling the sintering degree of the first grid line 211.

In some embodiments, the number and arrangement of the laser processing regions I and the non-laser processing regions II may be the same or different on both sides in the extending direction perpendicular to the first gate line 211.

In fig. 4, in the extending direction perpendicular to the first gate lines 211, the width of the laser processing region I is equal to the pitch between the adjacent first gate lines 211, for example, so that the adjacent first gate lines 211 commonly use carriers generated during the first laser processing of the same laser processing region I. In some embodiments, in the extending direction perpendicular to the first gate lines, the width of the laser processing region may be less than or equal to 1/2 of the interval between adjacent first gate lines, so that different first gate lines may respectively utilize carriers generated by the respective laser processing regions during the first laser processing, thereby facilitating the corresponding setting of the areas of the respective laser processing regions for the different first gate lines, so as to facilitate the regulation of the number of generated carriers.

In some embodiments, the ratio of the total length of the non-laser processing region II to the total length of the laser processing region I along the extending direction of the first gate line 211 is 2:1 to 4:1, for example, may be 2:1, 2.3:1, 3:1, 3.6:1 or 4:1.

In some embodiments, the length of the laser processing region I along the extending direction of the first gate line 211 ranges from 1 μm to 5 μm, for example, may be 1 μm, 1.5 μm, 2 μm, 2.4 μm, 3 μm, 3.6 μm, 4 μm, 4.7 μm, or 5 μm; the length of the non-laser treated region II is 3 μm to 7. Mu.m, for example, 3 μm, 3.3 μm, 4 μm, 4.6 μm, 5 μm, 5.9 μm, 6 μm, 6.5 μm or 7. Mu.m.

In some embodiments, the first laser processing is performed on the first surface 201 on both sides of the first gate line 211, and further includes: the first gate line 211 is subjected to a first laser process. It can be understood that when the spot size of the laser processed by the first laser is larger, the laser processed by the first laser can be further irradiated onto the first grid line 211, and the smaller the spot size of the laser is, the higher the corresponding spot is easy to generate, so that the damage on the surface of the material is overlarge, and when the spot size of the laser is larger, the damage of the laser to the first grid line 211 can be avoided, so that the laser processed by the first laser can be irradiated onto the first grid line 211.

FIG. 5 is a top view of another battery plate according to an embodiment of the present disclosure; fig. 6 is a schematic cross-sectional view of fig. 5 along the direction CC 1.

Referring to fig. 5 and 6, in some embodiments, the first surface 201 may include a first laser region a and a second laser region B, the first laser region a being located at two sides of the first grid line 211 in a direction extending perpendicular to the first grid line 211, the second laser region B being located at two sides of the first laser region a away from the first grid line 211, and an orthographic projection of the second grid line 212 on the first surface 201 being located within the second laser region B; performing a first laser process on the first surface 201 on both sides of the first gate line 211 includes: performing first laser treatment on the first laser region A; after the first laser processing, the method further comprises: and performing second laser processing on the second laser region B, and introducing second reverse current between the first grid line 211 and the second grid line 212, wherein the laser power of the second laser processing is larger than that of the first laser processing, and the second reverse current is larger than that of the first reverse current.

That is, the laser sintering of the first gate line 211 is performed in two steps, the laser irradiated region at the time of the first laser treatment is located adjacent to both sides of the first gate line 211, and the laser irradiated region at the time of the second laser treatment is located at a region spaced apart from the first gate line 211, so that the degree of sintering of the first gate line 211 can be more precisely controlled to facilitate adjustment of the process conditions of the second laser treatment according to the degree of sintering of the first laser treatment. Because of the spacing between the first gate lines 211 in the second laser region I, carriers generated by the second laser process reach under the first gate lines 211 more slowly than carriers generated by the first laser process, and accordingly, the laser power and the second reverse current of the second laser process can be appropriately increased compared to those of the first laser process. In addition, since the orthographic projection of the second gate line 212 on the first surface 201 is located in the second laser region B, the reverse current between the first gate line 211 and the second gate line 212 can interact with carriers faster, so as to promote the precipitation of metal micelles in the first gate line, so as to promote good ohmic contact between the first gate line 211 and the semiconductor material in the cell 200, and further facilitate the improvement of the filling factor and efficiency of the solar cell.

In fig. 5 and 6, carriers generated during the second laser processing by the same second laser region B are commonly used between adjacent first gate lines 211. In some embodiments, the second laser regions corresponding to the different first gate lines may be spaced apart from each other to each utilize carriers generated during the second laser processing by the different second laser regions.

In some embodiments, the first laser region may include alternately arranged laser processing regions and non-laser processing regions in an extending direction along the first gate line; performing a first laser treatment on the first laser region includes: performing first laser processing on the laser processing area of the first laser area only; performing a second laser treatment on the second laser region includes: and performing second laser treatment on all second laser areas.

That is, in the step of performing laser sintering on the first gate line by using the two-step laser sintering method, the irradiation of the first laser treatment may also adopt a virtual-real combination irradiation method, so as to be beneficial to accurately regulating and controlling the number of generated carriers, thereby being beneficial to controlling the sintering degree of the first gate line.

In some embodiments, the width of the second laser region B may be equal to the width of the second gate line 212 in the extending direction perpendicular to the first gate line 211. As such, the position of the second gate line 212 and the position of the second laser region B may completely correspond in a direction perpendicular to the first surface 201 to facilitate interaction between carriers and reverse current, facilitating laser sintering of the first gate line 211.

In some embodiments, the widths of the first laser regions a on both sides of the second laser region B are equal in the extending direction perpendicular to the first gate line 211. That is, the second laser region B is located right in the middle of two adjacent first gate lines 211, and the sizes of the first laser regions a corresponding to the adjacent first gate lines 211 are equal, so that it can be avoided that the number of carriers generated in the first laser processing or the second laser processing is different due to different areas of the first laser regions a and the second laser regions B corresponding to different first gate lines 211, and the number of carriers can be regulated and controlled by the laser irradiation area.

In some embodiments, the ratio of the width of the first laser area a to the width of the second laser area B along the extending direction perpendicular to the first gate line 211 may be in a range of 0.6-1.6, for example, 0.6, 0.8, 1, 1.1, 1.3, 1.5 or 1.6.

In some embodiments, the width of the first laser region a is 60 μm to 100 μm, for example, 60 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm in the extending direction perpendicular to the first gate line 211; the width of the second laser region B is 60 μm to 100 μm, and may be 60 μm, 70 μm, 75 μm, 80 μm, 85 μm, 90 μm, 95 μm or 100 μm, for example.

According to some embodiments of the present application, another aspect of the embodiments of the present application further provides a solar cell, which is formed by using the preparation method of the solar cell in any one of the embodiments of the present application, so as to improve efficiency of the solar cell. It should be noted that, in the same or corresponding parts as those of the above embodiments, reference may be made to the corresponding descriptions of the above embodiments, and detailed descriptions thereof will be omitted.

In some embodiments, the solar cell may be one of a PERC cell (Passivated Emitter and Rear Cell, passivated emitter and back cell), a PERT cell (Passivated Emitter and Rear Totally-diffused cell, passivated emitter back surface full diffusion cell), a TOPCON cell (Tunnel Oxide Passivated Contact, tunnel oxide passivation contact cell), a HIT/HJT cell (Heterojunction Technology, heterojunction cell).

In some embodiments, the solar cell may be a single-sided cell, such that the first surface 201 of the cell 200 may serve as a light receiving surface for receiving incident light, and the second surface 202 may serve as a backlight surface. In some embodiments, the solar cell may also be a double-sided cell, and the first surface 201 and the second surface 202 of the cell 200 may both be light-receiving surfaces, and may both be used for receiving incident light.

According to some embodiments of the present application, there is also provided a photovoltaic module according to another aspect of the embodiments of the present application, including: in at least one solar cell of the foregoing embodiment, the same or corresponding parts as those of the foregoing embodiment may be referred to for corresponding description of the foregoing embodiment, and detailed description thereof will not be repeated.

The photovoltaic module may further include a connection part for interconnecting the solar cells and converging current to be transmitted to an element outside the photovoltaic module. In some embodiments, the connection component may include a bus ribbon for connecting the photovoltaic cell string and the junction box, and an interconnect ribbon for connecting adjacent solar cells.

The photovoltaic module may also include a glue film. The adhesive film covers the surface of the solar cell. The adhesive film can be made of organic packaging adhesive films such as ethylene-vinyl acetate copolymer (EVA) adhesive film, polyethylene Octene Elastomer (POE) adhesive film or polyvinyl butyral (PVB) adhesive film.

The photovoltaic module may further include a cover plate covering a surface of the adhesive film remote from the solar cell. The cover plate can be a glass cover plate, a plastic cover plate and the like with a light transmission function. Specifically, the surface of the cover plate facing the adhesive film may be a concave-convex surface, so as to increase the utilization rate of incident light.

It will be understood by those of ordinary skill in the art that the foregoing embodiments are specific examples of implementing the present application and that various changes in form and details may be made therein without departing from the spirit and scope of the present application.

Claims

1. A method of manufacturing a solar cell, comprising:

providing a battery piece, wherein the battery piece comprises a first surface and a second surface which are opposite, the first surface is provided with a plurality of first grid lines, the second surface is provided with a plurality of second grid lines, and the orthographic projection of the first grid lines on the first surface and the orthographic projection of the second grid lines on the first surface are not overlapped;

and carrying out first laser treatment on the first surfaces on two sides of the first grid line, and introducing first reverse current between the first grid line and the second grid line, wherein the ratio of the laser power of the first laser treatment to the preset power is 1-1.1, and the ratio of the first reverse current to the preset current is 1-1.25, wherein the preset power and the preset current are the corresponding laser power and reverse current when the front projection of the first grid line on the first surface overlaps with the front projection of the second grid line on the first surface, and carrying out laser treatment on the first surfaces on two sides of the first grid line, and introducing the reverse current between the first grid line and the second grid line, so that PN junctions of the first grid line and the second grid line are broken down.

2. The method of manufacturing a solar cell according to claim 1, wherein the first surfaces on both sides of the first grid line include laser-treated areas and non-laser-treated areas alternately arranged in an extending direction along the first grid line;

the first laser processing on the first surfaces on two sides of the first grid line comprises the following steps: and carrying out the first laser treatment on the laser treatment areas on two sides of the first grid line.

3. The method of claim 2, wherein a ratio of a total length of the non-laser-treated region to a total length of the laser-treated region in an extending direction along the first gate line is 2:1 to 4:1.

4. The method of manufacturing a solar cell according to claim 3, wherein the length of the laser processing region is in a range of 1 μm to 5 μm in the extending direction along the first grid line; the length of the non-laser treatment area ranges from 3 mu m to 7 mu m.

5. The method of manufacturing a solar cell according to claim 1, wherein the first laser processing is performed on the first surfaces on both sides of the first grid line, further comprising: and carrying out the first laser processing on the first grid line.

6. The method of claim 1, wherein the first surface comprises a first laser region and a second laser region, the first laser region is located at two sides of the first grid line in a direction perpendicular to the first grid line, the second laser region is located at two sides of the first laser region away from the first grid line, and an orthographic projection of the second grid line on the first surface is located in the second laser region;

the first laser processing on the first surfaces on two sides of the first grid line comprises the following steps: performing the first laser treatment on the first laser region;

after the first laser processing, the method further comprises: and performing second laser processing on the second laser region, and introducing second reverse current between the first grid line and the second grid line, wherein the laser power of the second laser processing is larger than that of the first laser processing, and the second reverse current is larger than that of the first reverse current.

7. The method of manufacturing a solar cell according to claim 6, wherein the first laser regions include alternately arranged laser processing regions and non-laser processing regions in an extending direction along the first gate line;

performing a first laser treatment on the first laser region includes: performing the first laser processing only on the laser processing region of the first laser region;

performing a second laser treatment on the second laser region includes: and carrying out the second laser treatment on all the second laser areas.

8. The method of manufacturing a solar cell according to claim 6, wherein a width of the second laser region is equal to a width of the second gate line in an extending direction perpendicular to the first gate line.

9. The method of manufacturing a solar cell according to claim 6, wherein the widths of the first laser regions on both sides of the second laser region are equal in an extending direction perpendicular to the first gate line.

10. A solar cell, characterized in that the solar cell is formed by the method for manufacturing a solar cell according to any one of claims 1 to 9.

11. A photovoltaic module, comprising:

at least one solar cell according to claim 10;

the adhesive film covers the surface of the solar cell;

and the cover plate covers the surface of the adhesive film, which is far away from the solar cell.